Vehicles with all wheel drive:

For vehicles with all wheel drive, the three senders for fuel gauge are connected in sequence.

The central connector for all sensors is located on right below the rear seat bench.
Remove rear seat bench.
See SEAT BENCH, REMOVING AND INSTALLING .
Unscrew cover for connector flange at right beneath rear seat bench
Carefully disengage and disconnect 4-pin harness connector (arrow).

Fig 1: Disconnecting 4-Pin Harness Connector (All Wheel Drive)

Courtesy of AUDI OF AMERICA, INC.

NOTE: Terminal assignment for vehicles with front and all wheel drive is identical.